Come on, babe, U know I disagree, based on my actual experience! I gave $50 for this amazing WD Black I am on, it was a major coup for me; one of the best things I evah did.
I'm not saying not to buy used drives, if they are of a model that you prefer or have good experience with, only that you should only do it if you get a really good deal on one. Paying a higher price for a used drive because you have some sort of emotional attachment to that model is irrational, if you could get a more modern high-performance drive for the same or lower price.
I know that they're older, but I am a fan of the WD 6400AAKS drives. Had three of them at one point, AFAIK, they're all still running, 5+ years later. Well-built drives. If I could find more of them, I would consider purchasing them, but not for $50, maybe $25 at most. If I were to buy new drives, I would get the 1TB-per-platter 1TB Seagate Barracuda drives (bought two from TD recently), the 1TB WD Blue drives, or the Toshiba retail-boxed 3TB 7200RPM drives (supposedly from Hitachi lineage, which is a good thing.)
Maybe more WD Black drives, but ONLY if they were on a significant sale. You're not paying extra for reliability, so much as you are paying extra for an extended warranty built into the purchase price. Since extended warranties on electronics items are rarely worth it, I don't generally buy WD Black HDDs.
The only reason that I picked up three of the 500GB WD Blacks was because they were on Shell-shocker at Newegg for $60 ea. I thought that was a reasonable premium for a 5-year warranty.